Steam generator



Sept. 26, 1944. RENZ 2,359,155

STEAM GENERATOR Filed Aug. '5, 1942 2 Sheets-Sheet l Qua am Patented Sept. 26, 1944 STEAM GENERATOR Alfred F. Renz, Milwaukee, Wis, Morheat Corporation, Milwaukee,

poration of Wisconsin Application August 5, 1942, SerialNo. 453,677

4 Claims.

This invention relates to steam boilers or generators and has as a general object the provision of a steam generator in which steam can be produced within an exceptionally short period of time. i

In its broad aspect, this invention follows the principle embodied in patent No. 1,639,737, issued to Leo I. Kelly, August 23, 1927. As in the Kelly patent, the steam generator of this invention comprises a plurality of water coils arranged with their convolutions forming substantially vertical water tubes in which the water courses up and down as it flows from one convolution to the other.

Water is supplied to all of the convolutions at their lower portions, and their upper portions are connected with a steam dome into which the generated steam flows, the water which passes into the dome with the steam being returned for recirculation through the coils.

In a generating plant of this type where the steam generation is extremely rapid, it is essential that the water passages exposed to the direct heat be continuously supplied with water to preclude scale formation and pitting.

It is therefore an object of the present invention to improve the design and construction of steam generators of this type to the end that water continuously flows to the upright tubes at relatively high velocity to thereby preclude steaming until the water reaches the upright tubes.

Another object of this invention is to provide a steam generator so constructed that a substantial temperature differential obtains between the tubes and water passages subjected to the direct heat and the supply manifold from which the tubes are fed to thus accelerate the flow of water into the tubes. With a further view-toward insuring the continued supply of water to the tubes and passages directly exposed to the heat, it is another object of this invention to coordinate a balancing tank so located as to assure the retention of water in the tubes, with the supply manifold to assure an adequate supply of water to the manifold.

With the above and other objects in view,

which will appear as the description proceeds, i

this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one assignor to Wis, a corcomplete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a perspective view of a steam generating unit embodying this invention, said view having parts thereof broken away and in section;

Figure 2 is a vertical sectional view through the unit; and

Figure 3 is a horizontal cross sectional View taken through Figure 2 0n the plane of the line 3-3 with the walls of the combustion chamber indicated by light dot anddash lines,

Referringnow particularly to the accompanying drawings, in which like numerals indicate like parts, the numeral 5 designates generally the combustion chamber of a steam generating unit constructed in accordance with this invention and which comprises a lower fire ot 6 and an upper tube chamber 1. The walls of the entire combustion chamber are of high temperature heat insulating material suitably steel jacketed.

An oil burner 8 or other desirable source of heat projects a flame into the fire pot B, and combustion gases are carried off through a chime ney flue 9.

Within the tube chamber '1 are located the water passages or coils, indicated generally by the numeral Ill. These coils are substantially oval shaped and are so mounted that the sides of the oval provide vertical tube lengths I and the curved ends are connected to upper and lower headers l2 and I3, respectively. Registering openings at the junctures of the curved ends of the coil convolutions and the headers establish communication therebetween to enable the admission of water into the coils at the bottom and the discharge of steam at the top while allowing continuous circulationof water through the coils.

The upper headers l2 have their end portions bent upwardly and inwardly and connected to an upper manifold M which serves as a steam dome. The ends of the lower headers l3 project through the heat insulating walls of the combustion chamber and are bent downwardly and connected to a lower manifold [5.

The lower manifold l5 consists of a substantially U-shaped pipe laid horizontally in th wall of the fire pot but with a substantial thickness of heat insulating material between it and the interior of the fire pot or combustion chamber. The lower manifold l5 and the outer ends of the headers [3 connected thereto thus are insulated from the zone of heat application so that the temperature at the lower manifold is substantially less than the temperature at the junctures of the lower header with the coils.

A return water passage I6 having a balancing tank I! interposed therein connects the upper and lower headers exteriorly of the combustion chamber. This return passage, together with the vertical tubes, the manifolds and the headers, forms a circulatory water system with the balancin tank maintaining an adequate supply of water at a level which assures the retention of water in the tubes.

The steam generated is drawn from the upper manifold or dome l4 by a main steam line 18 which may connect with any steam conversion device (not shown) such as the radiators of a domestic heating installation.

By virtue of the temperature differential between the lower manifold and the portions of the headers exposed to the direct heat, water flows at high velocity from the lower manifold through the lower headers and into the upright tubes. Not only does the high velocity of the water flow per se preclude scale formation, but further, by keeping the headers completely filled with relatively colder water, steam formation is precluded until the water reaches the upright tubes where scale cannot readily form.

Scale is the flaking of metal from the tubes resulting from insulation of the water from the tube wall either by hardened sediment or by steam in the tube. Pitting is the weakening of the tube wall as a result of flaking.

Hence, by keeping the headers filled with water moving to the tubes at relatively high velocity, scale formation and pitting are avoided.

In addition, it is to be observed that through the increased velocity of the circulation resulting from the temperature di'iferential at the lower manifold and the water passages exposed to the direct heat the coldest water is always over the greatest heat. This assures eificient heat transfer.

The high velocity of the water flow through the water passages carries along any extraneous matter in the water for collection in the balancing tank I! where it settles to drop down into the manifold feeder IS. A drain plug 20 in this feeder affords access to the sediment accumulation and permits ready removal of the same.

Although the manner in which the arrangement of the upright tubes and their connections with the upper and lower headers enables the water to circulate through the successive convolutions forms no direct part of this invention,

having been disclosed in the aforesaid Kelly patent, a brief description thereof will facilitate an understanding of the complete Operation of the generator.

Assuming that the unit is cold and that the thermostat controllin th oil burner calls for heat: at this instant the water in the ystem is quiescent, standing in the upright tubes at a level determined by the level of the water in the balancing tank 11.

As the tubes are heated the water therein begins to boil and tends to rise in all of the tubes.

-However, the instant the rising water in one of the two tubes forming a convolution overbalances the rise in the other tube of the convolution to the extent that the water rises to the top of the loop, circulation commences and thereafter the water circulates in one direction through the convolutions of the coil. Thus in the coil portion at one side of a median vertical plane the Water nection with the accompanying drawings, it

will be readily apparent to those skilled in the art that this invention provides a steam generator having many advantages over past generators and boilers not only in that it greatly speeds up steam generation, but in that it practically eliminates scale and the objectionable consequences thereof. 7

What I claim as my invention is:

l. A steam generator comprising: an upright combustion chamber; a manifold providing a steam dome in the upper portion of the combus: tion chamber; a plurality of looped upper headers having their ends connectedto said manifold and having their medial portions extending transversely across the combustion chamber un der said manifold; a plurality of spaced parallel lower headers extending transversely across the combustion chamber beneath and substantially parallel with said upper headers; substantially oval shaped coils having their curved ends connected to said upper and lower headers to communicate the same and having their straight portions disposed vertically within the combustion chamber; the ends of the lower headers extending through the adjacent walls of the combustion chamber and being bent downwardly exteriorly of said walls; manifolds on the exterior of said walls to which the ends of said lower headers are connected; and a connection between said upper and lower manifolds outside the combustion chamber through which water may flow from the upper to the lower manifold.

2. A steam generator comprising: an upright combustion chamber; a manifold providing a steam dome in the upper portion of the combustion chamber; a plurality of looped upper headers having their ends connected to said manifold and having their medial portions extending transversely across the combustion chamber under said manifold; a plurality of spaced parallel lower headers extending transversely across the combustion chamber beneath and substantially parallel with said upper headers; substantially oval shaped coils having their curved ends connected to said upper and lower headers to communicate the same and having their straight portions disposed vertically within the combustion chamber; the ends of the lower headers extending through the adjacent walls of the combustion chamber and being bent downwardly exteriorly of said walls; manifolds on the exterior of said walls to which the ends of said lower headers are connected; a connection between said upper and lower manifolds outside the combustion chamber through which water may flow from the upper to the lower manifold; and a balancing tank in said connection, said balancing tank being at a substantial elevation above the inside the combustion chamber and their junctures with th lower manifolds outside the combustion chamber together with the disposition of said lower headers above that of the lower manifolds insuring rapid continuous passage of water from said manifolds into the headers and the coils connected thereto.

3. A steam generator of the character described, comprising: an upright combustion chamber adapted to be fired at the bottom and having spaced side walls; a manifold extending horizontally across the exterior of each ofsaid side walls; a plurality of horizontal lower headers having down turned ends extending across the combustion chamber at an elevation above that of said manifolds with the ends thereof projecting through the spaced side walls and connected to the adjacent manifolds? a plurality of substantially horizontal headers extending across the upper portion of the combustion chamber above and substantially parallel with said lower headers, the ends of said upper headers being turned upwardly and inwardly; an upper manifold to which the ends of said upper headers are connected, said upper manifold providing a steam dome; and duct means connecting the upper and lower manifolds on the exterior of the combustion chamber.

4. A steam generator of the character described, comprising: an upright combustion chamber; a manifold in the upper portion of the combustion chamber; a plurality of upper headers each comprising a substantially horizontal tube extending transversely of and beneath said upper manifold and having end portions bent upwardly and inwardly and connected to the upper manifold; a plurality of lower headers at a substantial distance below the upper headers and substantially parallel therewith; a plurality of vertical tubes connecting the upper and lower headers; substantially horizontal lower manifolds, one

adjacent to each of two opposite Walls of the combustion chamber and to which the adjacent ends of the lower headers are connected; and duct means connecting the upper manifold with said lower manifolds, said duct means including a balancing tank adapted to maintain a constantly available head of water above the lower headers and their connections to the lower manifolds.

ALFRED F. RENZ. 

